Vented Bushing for Ophthalmic Lens Molds
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Solution Overview
Problem
Existing injection molding systems for ophthalmic lens molds face issues with gas pressure buildup and residual component accumulation, leading to positional changes of optic power inserts, which affect lens mold quality and consistency, increasing manufacturing time and costs.
Innovation Solution
The introduction of vented bushings with a corrugated interior sidewall surface and microchannels to effectively vent gases during the injection molding process, maintaining positional stability of optic power inserts and reducing residual component accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional smooth-bore bushings are used to accommodate optic power inserts, then the inserts can be sealed and protected, but gas pressure buildup occurs during injection molding causing positional changes of the inserts
Solution Approach 1:
The patent extracts the harmful gas from the mold cavity by introducing vent channels into the bushing structure. These channels provide a dedicated pathway for gas to escape during injection molding, preventing gas pressure buildup that would otherwise cause optic power inserts to shift position. The vent channels are integrated into the bushing without compromising the sealed accommodation of the inserts.
Solution Approach 2:
The vent channels act as an intermediary mechanism between the mold cavity and the external environment. They mediate the gas pressure issue by providing a controlled escape route, allowing the system to maintain both the sealed protection of optic power inserts and the release of harmful gases during the molding process.
2Object-generated harmful factors
If vents are provided in conventional injection molding systems, then gas can be released, but residual components accumulate and optic power inserts still shift position
Solution Approach 1:
The patent applies local quality by providing vent channels at specific locations within the bushing structure, particularly near the optic power inserts. The corrugated interior sidewall surface is applied locally to the inner surface of the bushing, creating localized friction that prevents insert movement while the vent channels handle gas release. This localized application of different surface properties solves both gas release and position stability requirements.
Solution Approach 2:
The bushing structure combines different surface properties - smooth vent channels for gas flow and corrugated friction surfaces for position stabilization. This composite approach within a single component allows simultaneous achievement of gas release and prevention of insert shifting during injection molding.
3Ease of operation
If smooth internal bore bushings are used, then optic power inserts can be easily inserted and removed, but residual component accumulation increases manufacturing time and costs
Solution Approach 1:
The bushing interior surface is segmented into different functional zones: smooth vent channels for gas release and corrugated friction surfaces for preventing residual accumulation. This segmentation allows the bushing to perform multiple functions - easy insert removal through the smooth vent paths while preventing residual buildup through the corrugated surfaces that reduce material adhesion.
Solution Approach 2:
The corrugated interior sidewall surface creates a micro-rough structure that prevents residual polymer material from adhering to the bushing walls. This textured surface allows for easier removal of optic power inserts by reducing the accumulation of residual components that would otherwise create friction and increase manufacturing time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces gas pressure buildup, minimizes positional misalignment, and enhances the quality and consistency of ophthalmic lens molds, resulting in improved manufacturing efficiency and reduced production costs.
Implementation Method 1
The venting system is effective to direct gas from a first end of the bushing toward a second end of the bushing along the length of the bushing and between an optic power insert located in the bore and the interior sidewall surface
Data Source
AI summary
Devices, systems, and methods for producing ophthalmic lens molds and molded ophthalmic lenses are described. The present devices, systems, and methods provide venting of gases produced during injection molding of ophthalmic lens molds. With the present devices, systems, and methods, improvements in mold quality, lens quality, mold quality consistency, and lens quality consistency can be achieved compared to existing injection molding devices, systems, and methods. An optic power insert bushing is described and includes a venting system that directs gas from a first end of the bushing toward a second end of the bushing. The gas is directed between an optic power insert and an inner sidewall surface of a bushing bore in which the optic power insert is located. The bushing or bushings, and optic power inserts, can be provided as components of an ophthalmic lens mold injection system. Methods of making and using the vented bushings are also described.